GraphQL\Validator\Rules\QueryDepth::__invoke PHP Method

    public function __invoke(ValidationContext $context)
    {
        return $this->invokeIfNeeded($context, [NodeKind::OPERATION_DEFINITION => ['leave' => function (OperationDefinitionNode $operationDefinition) use($context) {
            $maxDepth = $this->fieldDepth($operationDefinition);
            if ($maxDepth > $this->getMaxQueryDepth()) {
                $context->reportError(new Error($this->maxQueryDepthErrorMessage($this->getMaxQueryDepth(), $maxDepth)));
            }
        }]]);
    }